Non-contact sensor with particular utility for measurement of road profile

Claim 1

Apparatus for measuring distance to a surface comprising first means for directing a light beam onto said surface; second means including optically sensitive position detection means, and means for receiving light reflected by said surface and directing said reflected light onto said detection means, said detection means providing a pair of signal A and B as a function of orthogonal position coordinates of such reflected light incident on said detection means; means for providing a signal A-B as a function of a difference between said signals A and B; means for providing a signal A+B as a function of a sum of said signals A and B; means for indicating distance to the surface as a function of a ratio P of said difference signal A-B to said sum signal A+B; means mounting said first and second means to establish a frame of reference spaced by a nominal distance H from the surface, said apparatus being constructed to measure departure X of the surface from said nominal distance H within a measurement window W, said first and second means being separated by said mounting means by a distance L; and means for determining said distance X as a function of the equation: X=(P*K1)/(K2+P*K3), where K1 is a constant equal to (L 2 +H 2 ) 1/2 , K2 is a constant equal to F sin(a), K3 is a constant equal to cos(a), a is angle of orientation between said first and second means at said nominal distance H, and F equals image distance.

Claim 5

A system for measuring and recording road surface profile as a function of distance between successive increments of road surface and a vehicular inertial frame of reference traveling over the road surface, comprising first means mounted in fixed position with respect to a vehicle frame for directing a measurement light beam onto a road surface beneath the frame, second means mounted in fixed position on said frame spaced from said first means for receiving light energy from said first means reflected by the road surface, said second means including photosensitive means for providing a pair of output signals which vary as respective functions of orthogonal position coordinates of such reflected light incident on said detection means, third means for measuring distance to the road surface as a function of said pair of output signals at said detection means, and means responsive to incremental displacement of the vehicle over the road surface for sampling and storing successive measurements of said distance.

Claim 6

A system for measuring and recording road surface profile as a function of distance between successive increments of road surface and a vehicular inertial frame of reference traveling over the road surface, comprising first means mounted in fixed position with respect to a vehicle frame for directing a measurement light beam onto a road surface beneath the frame, second means mounted in fixed position on said frame spaced from said first means for receiving light energy from said first means reflected by the road surface, said second means including photosensitive means for providing a pair of output signals which vary as respective functions of orthogonal position coordinates of such reflected light incident on said detection means, third means for measuring distance to the road surface as a function of said pair of output signals at said detection means, and means responsive to incremental displacement of the vehicle over the road surface for sampling and storing successive measurements of said distance.